Novel voltage transformer suitable for broadband voltage measurement

Abstract

The invention relates to the technical field of voltage transformers, in particular to a novel voltage transformer suitable for broadband voltage measurement, which comprises a frame mechanism, an insulating sleeve, a working part arranged on the insulating sleeve, an auxiliary part arranged on the insulating sleeve, a supporting part arranged on the insulating sleeve and a core mechanism, comprising an upper bridge arm part arranged in an insulating sleeve, a lower bridge arm capacitive voltage divider arranged on the upper bridge arm part, a converter arranged on the lower bridge arm capacitive voltage divider, an inverter arranged on the converter, a voltage transformer which is developed based on a capacitive voltage dividing principle and has a novel structure, and the capacitive voltage divider is used as a sensor. The high-voltage arm and the low-voltage arm are both capacitors, the broadband voltage transformer is used for signal isolation and voltage output, and the capacitors are high in withstand voltage and less affected by distributed capacitance, so that the broadband voltage transformer is widely applied to a high-voltage power grid and is suitable for trial and popularization of field application.

Description

Technical Field

[0001] The invention relates to the technical field of voltage transformers, and in particular to a novel voltage transformer suitable for wide-band voltage measurement. Background Art

[0002] Under the background of new power system construction, the large-scale application of power electronic equipment has caused the dynamic characteristics of the new power system to be complex and changeable, and the problem of harmonic measurement and control has become prominent. However, the voltage transformers currently configured in 110kV and above power plants are mostly capacitive voltage transformers (CVTs), and their harmonic measurement errors are as high as more than 80%. There are some research results on the use of CVT for accurate harmonic measurement, but there are certain problems, which has prevented it from being widely used in actual projects, and the harmonic test error problem of CVT has not been fundamentally solved. The harmonic measurement method based on CVT capacitor current has high requirements on the accuracy and broadband characteristics of the transformer, and the CVT secondary circuit needs to be modified. It is also susceptible to electromagnetic interference and thus affects the measurement accuracy. At present, there is little research on the harmonic transfer characteristics of the transformer and the influence of harmonics on error accuracy. The electromagnetic interaction inside the CVT is complex, and there is a lack of new CVT devices with high accuracy that meet the broadband harmonic and time-varying characteristics.

[0003] To this end, we proposed a new voltage transformer suitable for wide-band voltage measurement to solve the above problems. Summary of the invention

[0004] In view of the above-mentioned problems that the existing voltage transformer has a small measurement range and low measurement accuracy, the present invention is proposed.

[0005] Therefore, the purpose of the present invention is to provide a new type of voltage transformer suitable for broadband voltage measurement, and its purpose is to achieve high-accuracy measurement of broadband harmonics and time-varying characteristics.

[0006] To solve the above technical problems, the present invention provides the following technical solutions: A new voltage transformer suitable for wide-band voltage measurement, comprising a frame mechanism, including an insulating bushing, a working part arranged on the insulating bushing, an auxiliary part arranged on the insulating bushing, and a supporting part arranged on the insulating bushing;

[0007] The core mechanism comprises an upper bridge arm part arranged inside the insulating sleeve, a lower bridge arm capacitor voltage divider arranged on the working part, a converter arranged on the lower bridge arm capacitor voltage divider, and an inverter arranged on the converter.

[0008] As a preferred solution of the novel voltage transformer suitable for wide-band voltage measurement of the present invention, the accessory part further comprises an end cover arranged on the insulating bushing and a flange plate arranged on the insulating bushing.

[0009] As a preferred solution of the novel voltage transformer suitable for broadband voltage measurement of the present invention, the support portion includes a base frame arranged on the insulating bushing, the base frame is a cross-shaped cross structure, and includes a plurality of fixed pillars arranged on the base frame.

[0010] As a preferred solution of the novel voltage transformer suitable for broadband voltage measurement of the present invention, the working part includes a bottom barrel arranged on the insulating sleeve, a fixing frame arranged on the bottom barrel, and an air chamber arranged inside the bottom barrel.

[0011] As a preferred solution of the novel voltage transformer suitable for broadband voltage measurement of the present invention, the air chamber is filled with insulating gas, and the air pressure in the air chamber is.

[0012] As a preferred solution of the novel voltage transformer applicable to wide-band voltage measurement of the present invention, the upper bridge arm comprises an epoxy board arranged inside the insulating sleeve, and a capacitor arranged on the epoxy board;

[0013] As a preferred solution of the novel voltage transformer suitable for broadband voltage measurement of the present invention, the capacitors are fixed in series on the upper and lower surfaces of the epoxy board in a spiral parallel ascending manner, and the angle between the adjacent capacitors on the upper and lower surfaces is 60°.

[0014] As a preferred solution of the new voltage transformer suitable for wide-band voltage measurement of the present invention, the transformer includes an iron core, a secondary winding arranged on the iron core, a primary winding arranged on the secondary winding, and a shielding film arranged between the primary winding and the secondary winding.

[0015] As a preferred solution of the novel voltage transformer suitable for broadband voltage measurement of the present invention, the transformer further comprises a long-side magnetic shielding plate arranged on the iron core and a short-side magnetic shielding plate arranged on the iron core.

[0016] As a preferred solution of the new voltage transformer suitable for wide-band voltage measurement of the present invention, the working part also includes an inflation nozzle arranged on the bottom barrel, a gas meter box arranged on the bottom barrel, a junction box arranged on the bottom barrel, and two terminal posts arranged inside the junction box.

[0017] The beneficial effects of the present invention are as follows: a voltage transformer of a new structure is developed based on the principle of capacitor voltage division, a capacitor voltage divider is used as a sensor, high and low voltage arms are both capacitors, and a wide-band voltage transformer is used for signal isolation and voltage output. Unlike the traditional capacitive voltage transformer, this new voltage transformer has no resonant inductor, so there is no problem of narrow frequency band caused by resonant frequency selection. The signal at its low voltage end can be directly output to a measuring meter or sent to a secondary merging unit through digital processing. Since the capacitor has a high withstand voltage and is less affected by distributed capacitance, it is widely used in high-voltage power grids and is suitable for pilot and promotion of field applications. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for describing the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work. Among them:

[0019] Figure 1 The figure is a schematic diagram of the overall structure of a novel voltage transformer suitable for wide-band voltage measurement according to the present invention.

[0020] Figure 2 The figure is a schematic diagram of the cross-sectional structure of a novel voltage transformer suitable for wide-band voltage measurement according to the present invention.

[0021] Figure 3 The schematic diagram of the structure of the novel voltage transformer converter suitable for wide-band voltage measurement of the present invention is shown in FIG.

[0022] Figure 4 The present invention is a schematic structural diagram of a novel voltage transformer fixing frame suitable for broadband voltage measurement. DETAILED DESCRIPTION

[0023] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are described in detail below in conjunction with the accompanying drawings.

[0024] In the following description, many specific details are set forth to facilitate a full understanding of the present invention, but the present invention may also be implemented in other ways different from those described herein, and those skilled in the art may make similar generalizations without violating the connotation of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0025] Secondly, the term "one embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The term "in one embodiment" that appears in different places in this specification does not necessarily refer to the same embodiment, nor does it refer to a separate or selective embodiment that is mutually exclusive with other embodiments.

[0026] Secondly, the present invention is described in detail with reference to the schematic diagram. When describing the embodiments of the present invention in detail, for the sake of convenience, the cross-sectional diagrams showing the device structure will not be partially enlarged according to the general scale, and the schematic diagrams are only examples, which should not limit the scope of protection of the present invention. In addition, in actual production, the three-dimensional dimensions of length, width and depth should be included.

[0027] Example 1

[0028] Reference Figure 1 , which is the first embodiment of the present invention, provides a novel voltage transformer suitable for wide-band voltage measurement, including a frame mechanism 100, including an insulating sleeve 101, a working portion 102 arranged on the insulating sleeve 101, an auxiliary portion 103 arranged on the insulating sleeve 101, and a supporting portion 104 arranged on the insulating sleeve 101;

[0029] The core mechanism 200 includes an upper bridge arm portion 201 disposed inside the insulating sleeve 101 , a lower bridge arm capacitive voltage divider 202 disposed on the working portion 102 , a converter 203 disposed on the lower bridge arm capacitive voltage divider 202 , and an inverter 204 disposed on the converter 203 .

[0030] Furthermore, the upper bridge arm 201 and the lower bridge arm capacitor divider 202 are connected by wires, the frequency range of the inverter 204 is 50 Hz to 2500 Hz, the effective value error is ≤3%, and the number of frequency verification points is ≥50.

[0031] Specifically, the device adopts a voltage transformer of a new structure developed based on the principle of capacitor voltage division, uses a capacitor voltage divider as a sensor, and the high and low voltage arms are capacitors. The wide-band voltage transformer is used for signal isolation and voltage output. Unlike the traditional capacitive voltage transformer, this new type of voltage transformer has no resonant inductor, so there is no problem of narrow frequency band caused by resonant frequency selection. The signal at its low voltage end can be directly output to the measuring meter or sent to the secondary merging unit through digital processing. Since the capacitor has a high withstand voltage and is less affected by distributed capacitance, it is widely used in high-voltage power grids and is suitable for pilot and promotion of field applications. Secondly, effective compensation and cancellation are performed through the inverter 204 to improve the measurement accuracy of the transformer.

[0032] Example 2

[0033] Reference Figure 1, which is the second embodiment of the present invention. This embodiment is different from the first embodiment in that the attachment 103 also includes an end cover 103 a disposed on the insulating sleeve 101 and a flange 103 b disposed on the insulating sleeve 101 .

[0034] The support portion 104 includes a base frame 104 a disposed on the insulating sleeve 101 . The base frame 104 a is a cross-shaped structure and includes a plurality of fixing pillars 104 b disposed on the base frame 104 a .

[0035] The working part 102 includes a bottom barrel 102a disposed on the insulating sleeve 101, a fixing frame 102b disposed on the bottom barrel 102a, and an air chamber 102c disposed inside the bottom barrel 102a.

[0036] Furthermore, a long socket is designed on the inner diameter of the end cover 103 a for fixing the upper bridge arm 201 .

[0037] The interior of the gas chamber 102c is filled with SF6 insulating gas, and the gas pressure in the gas chamber 102c is 0.2 MPa.

[0038] The working part 102 further includes an air filling nozzle 102d disposed on the bottom barrel 102a, a gas meter box 102e disposed on the bottom barrel 102a, a junction box 102f disposed on the bottom barrel 102a, and two terminal posts 102g disposed inside the junction box 102f.

[0039] The remaining structure is the same as that of Example 2.

[0040] Example 3

[0041] Reference Figure 1 , which is the third embodiment of the present invention. This embodiment is different from the second embodiment in that: the upper bridge arm 201 includes an epoxy board 201a disposed inside the insulating sleeve 101, and a capacitor 202b disposed on the epoxy board 201a;

[0042] The upper end of the epoxy board 201a is connected to the flange 103b, and the lower end is connected to the lower bridge arm capacitor divider 202; the lower end of the epoxy board 201a is inserted into the fixing frame 102b, and the upper end is fixed on the flange 103b, both of which are fixed by screws.

[0043] The capacitors 202b are fixed in series on the upper and lower surfaces of the epoxy board 201a in a spiral parallel ascending manner, and the angle between the adjacent capacitors 202b on the upper and lower surfaces is 60°, in order to save space while ensuring the insulation distance.

[0044] Specifically, a standard capacitor voltage-dividing structure is adopted, in which the dielectric loss of the capacitor is small, and the influence of the distributed capacitance on the voltage-dividing ratio at different frequencies can be overcome.

[0045] The transformer 203 includes an R-type core 203a, a secondary winding 203b disposed on the R-type core 203a, a primary winding 203c disposed on the secondary winding 203b, and a shielding film 203d disposed between the primary winding 203c and the secondary winding 203b.

[0046] The converter 203 further includes a long-side magnetic shielding plate 203f provided on the R-type core 203a and a short-side magnetic shielding plate 203e provided on the R-type core 203a.

[0047] Furthermore, the last turn of the primary winding 203c is connected to the shielding film 203d, and the last turn of the secondary winding is connected to the shielding film 203d, and the shielding film 203d is a copper foil shielding film.

[0048] Furthermore, the lower bridge arm voltage is set to 57.7V.

[0049] Specifically, the output signal of the conversion device adopts a multi-shielding design, which can effectively ensure the measurement accuracy of the new voltage transformer with a standard capacitor voltage divider structure under wide-band conditions.

[0050] The remaining structure is the same as that of Example 2.

[0051] Importantly, it should be noted that the construction and arrangement of the present application shown in a plurality of different exemplary embodiments are only exemplary. Although only a few embodiments are described in detail in this disclosure, it should be readily understood by those who refer to this disclosure that many modifications are possible (e.g., the size, scale, structure, shape and proportion of various elements, and parameter values ​​(e.g., temperature, pressure, etc.), installation arrangement, use of materials, color, directional changes, etc.) without substantially departing from the novel teachings and advantages of the subject matter described in the application. For example, the element shown as integrally formed can be composed of multiple parts or elements, the position of the element can be inverted or otherwise changed, and the nature or number or position of the discrete element can be changed or changed. Therefore, all such modifications are intended to be included in the scope of the present invention. The order or sequence of any process or method steps can be changed or reordered according to alternative embodiments. In the claims, any "device plus function" clause is intended to cover the structure of performing the function described herein, and is not only structurally equivalent but also equivalent structure. Without departing from the scope of the present invention, other replacements, modifications, changes and omissions can be made in the design, operating conditions and arrangement of the exemplary embodiments. Therefore, the invention is not limited to a specific embodiment, but extends to several modifications still falling within the scope of the appended claims.

[0052] Additionally, in order to provide a concise description of exemplary embodiments, all features of an actual embodiment (ie, those features that are not relevant to the best mode presently contemplated for carrying out the invention or those that are not relevant to implementing the invention) may not be described.

[0053] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present invention, which should all be included in the scope of the claims of the present invention.

Claims

1. A new voltage transformer suitable for broadband voltage measurement, characterized in that: It comprises a frame mechanism (100), an insulating sleeve (101), a working part (102) arranged on the insulating sleeve (101), an auxiliary part (103) arranged on the insulating sleeve (101), and a supporting part (104) arranged on the insulating sleeve (101); The core mechanism (200) comprises an upper bridge arm portion (201) arranged inside the insulating sleeve (101), a lower bridge arm capacitive voltage divider (202) arranged on the working portion (102), a converter (203) arranged on the lower bridge arm capacitive voltage divider (202), and an inverter (204) arranged on the converter (203).

2. The novel voltage transformer suitable for broadband voltage measurement according to claim 1 is characterized in that: The attachment part (103) further comprises an end cover (103a) arranged on the insulating sleeve (101) and a flange (103b) arranged on the insulating sleeve (101).

3. The novel voltage transformer suitable for broadband voltage measurement according to claim 1 is characterized in that: The support portion (104) comprises a base frame (104a) arranged on the insulating sleeve (101); the base frame (104a) is a cross-shaped structure and comprises a plurality of fixed pillars (104b) arranged on the base frame (104a).

4. The novel voltage transformer suitable for broadband voltage measurement according to claim 1 is characterized in that: The working part (102) comprises a bottom barrel (102a) arranged on the insulating sleeve (101), a fixing frame (102b) arranged on the bottom barrel (102a), and an air chamber (102c) arranged inside the bottom barrel (102a).

5. The novel voltage transformer suitable for broadband voltage measurement according to claim 4 is characterized in that: The gas chamber (102c) is filled with SF6 insulating gas, and the gas pressure in the gas chamber (102c) is 0.2 MPa.

6. The novel voltage transformer suitable for broadband voltage measurement according to claim 1 is characterized in that: The upper bridge arm (201) comprises an epoxy board (201a) arranged inside the insulating sleeve (101), and a capacitor (202b) arranged on the epoxy board (201a).

7. The novel voltage transformer suitable for broadband voltage measurement according to claim 6 is characterized in that: The capacitor (202b) is fixed in series on the upper and lower surfaces of the epoxy board (201a) in a spiral parallel ascending manner, and the angle between the upper and lower adjacent capacitors (202b) is 60°.

8. The novel voltage transformer suitable for broadband voltage measurement according to claim 1 is characterized in that: The converter (203) includes an R-type iron core (203a), a secondary winding (203b) arranged on the R-type iron core (203a), a primary winding (203c) arranged on the secondary winding (203b), and a shielding film (203d) arranged between the primary winding (203c) and the secondary winding (203b).

9. The novel voltage transformer suitable for broadband voltage measurement according to claim 1, characterized in that: The converter (203) further comprises a long-side magnetic shielding plate (203f) arranged on the R-type iron core (203a), and a short-side magnetic shielding plate (203e) arranged on the R-type iron core (203a).

10. The novel voltage transformer suitable for broadband voltage measurement according to claim 1, characterized in that: The working part (102) further comprises an air filling nozzle (102d) arranged on the bottom barrel (102a), a gas meter box (102e) arranged on the bottom barrel (102a), a junction box (102f) arranged on the bottom barrel (102a), and two junction posts (102g) arranged inside the junction box (102f).

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